102 Moll . 
MOLLUSCA. 
less, with a large U-shaped ossiculum fitting in the apices of the beaks, 
which are filled with solid shelly matter ; a strong external ligament, but 
for which the hinge line is not bent or thickened for B. elegans , n. sp., 
W. Indies, id. t. c. p. 309. 
Oetoconcha , n. sect. “ Shell differing from Poromya proper by the car- 
tilage being almost external and the fossettes diminished in size and up- 
turned, the external ligament consequently nearly obsolete for Lyonsia 
bulla , Dali ; contains also Pecchiolia tornata , Jeffr., Thracia uitida, 
Yerrill : id. t. c. p. 280. 
Poromya (Cetoconcha) albida , P. (C.) elongata, P. ((7.) margarita , 
n. spp., W. Indies, id. t. c. pp. 282 & 284. 
Thracia crassa , n. sp., Jan Mayen, Becher, p. 71, fig. 1 ; T. stimpsoni, 
n. sp., W. Indies, Dali, (3) p. 307. 
ADDENDA. 
To Section 5, Respiratory System, p. 33, add, “Possible absence of 
gills in Necera ; Dall (5).” 
To Section 11, Stray Biological Notes, pp. 45-47, add, — 
“ Zonites drajmrnaldi , kept for some years and fed in winter on meat 
iu lieu of vegetables ; did not thrive ; Hele (1) 
“ Leucochroa, sp., and Helix vermiculata, Midi., alive after two years’ 
confinement in a leaden case ; Reiniiaudt (1).” 
